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<head><meta charset="utf-8"><title>Advice for &quot;Extend well-known traits by Unpin&quot; · wg-traits · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/index.html">wg-traits</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html">Advice for &quot;Extend well-known traits by Unpin&quot;</a></h3>

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<a name="209290791"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209290791" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryleak47 <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209290791">(Sep 07 2020 at 12:36)</a>:</h4>
<p>Hey <span class="user-mention" data-user-id="232957">@Jack Huey</span>,<br>
It seems like chalk has incomplete support for auto traits, and thats why <a href="https://github.com/rust-lang/chalk/pull/603">https://github.com/rust-lang/chalk/pull/603</a> is insufficient.<br>
In particular, given some <code>auto trait Foo {}</code> in rustc then Slices, Arrays etc. implement Foo if the contained type implements Foo.<br>
This is not yet implement in chalk apparently.<br>
So I'm toying with extending push_auto_trait_impls by implementations for Slices, Arrays, etc.</p>
<p>Do you agree this is the right way of doing it?</p>



<a name="209292089"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209292089" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Florian Diebold <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209292089">(Sep 07 2020 at 12:50)</a>:</h4>
<p>just as a side note, if in the end there's no special support in Chalk needed for Unpin, then it's superfluous to even add it as a well-known trait</p>



<a name="209292804"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209292804" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryleak47 <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209292804">(Sep 07 2020 at 12:59)</a>:</h4>
<p>uh, thats a valid point. ^^'</p>



<a name="209293340"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209293340" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209293340">(Sep 07 2020 at 13:04)</a>:</h4>
<p>From the <a href="https://github.com/rust-lang/rfcs/blob/master/text/2349-pin.md#the-unpin-auto-trait">RFC</a>:</p>
<blockquote>
<p>This trait is a lang item, but only to generate negative impls for certain generators</p>
</blockquote>
<p>Sounds like chalk will need to handle that</p>



<a name="209293567"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209293567" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209293567">(Sep 07 2020 at 13:07)</a>:</h4>
<p>Unless every chalk integration handles that separately, but I think those impls can be generated in chalk</p>



<a name="209293907"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209293907" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> detrumi <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209293907">(Sep 07 2020 at 13:11)</a>:</h4>
<p>Hmm, not too clear on the specifics, but maybe it'll become clearer once generators are handled in chalk (there's a <a href="https://github.com/rust-lang/chalk/pull/593">WIP PR</a> for that), and we look into supporting <code>Future</code> in chalk?</p>



<a name="209294619"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209294619" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Florian Diebold <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209294619">(Sep 07 2020 at 13:18)</a>:</h4>
<p>I would imagine that would happen in the desugaring for generators/async functions, so outside Chalk</p>



<a name="209295550"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209295550" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Florian Diebold <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209295550">(Sep 07 2020 at 13:28)</a>:</h4>
<p>but... I don't know that well how those things work</p>



<a name="209310301"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209310301" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209310301">(Sep 07 2020 at 16:06)</a>:</h4>
<p>Yeah, auto traits not being implemented for builtin types is known. (I'm actually supposed to file an issue for that, which I haven't gotten to).</p>



<a name="209310374"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209310374" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209310374">(Sep 07 2020 at 16:07)</a>:</h4>
<p>Yeah, I guess <code>Unpin</code> being <code>auto</code> means this doesn't need to be a builtin type.</p>



<a name="209310473"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209310473" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209310473">(Sep 07 2020 at 16:09)</a>:</h4>
<p>I'm also not familiar with this, but I also imagine this is handled in the desugaring.</p>



<a name="209310494"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209310494" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209310494">(Sep 07 2020 at 16:09)</a>:</h4>
<p><span class="user-mention" data-user-id="335294">@memoryleak47</span> do you instead want to PR the fix for auto traits?</p>



<a name="209310584"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209310584" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryleak47 <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209310584">(Sep 07 2020 at 16:10)</a>:</h4>
<p>yup!</p>



<a name="209310668"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209310668" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryleak47 <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209310668">(Sep 07 2020 at 16:12)</a>:</h4>
<p>I'll close the current PR then?</p>



<a name="209312241"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209312241" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209312241">(Sep 07 2020 at 16:33)</a>:</h4>
<p>Hmm, I mean, you could leave it open. I would like either <span class="user-mention" data-user-id="116009">@nikomatsakis</span>'s or maybe <span class="user-mention" data-user-id="251766">@Areredify</span>'s thoughts on if <code>Unpin</code> needs to be builtin. Particularly since I'm not familiar with how rustc handles that.</p>



<a name="209315496"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209315496" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209315496">(Sep 07 2020 at 17:19)</a>:</h4>
<p>it needs to be builtin because you cant make a negative impl of Unpin for Generator</p>



<a name="209315821"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209315821" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209315821">(Sep 07 2020 at 17:24)</a>:</h4>
<p>see <code>librustc_trait_selection::traits::select::assemble_candidates_from_auto_impls</code></p>



<a name="209315839"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209315839" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209315839">(Sep 07 2020 at 17:25)</a>:</h4>
<p>uh wait its the old one</p>



<a name="209315983"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209315983" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209315983">(Sep 07 2020 at 17:27)</a>:</h4>
<p><a href="https://github.com/rust-lang/rust/blob/3e14b684dd31794e8dbe6acd7a5f132997ee0c47/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs#L373">link</a></p>



<a name="209316085"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316085" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316085">(Sep 07 2020 at 17:29)</a>:</h4>
<p>at least thats the only Unpin thing I found when researching what traits chalk needs to support</p>



<a name="209316193"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316193" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316193">(Sep 07 2020 at 17:31)</a>:</h4>
<p>Right, so this is really a question based on how generators in chalk will work</p>



<a name="209316286"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316286" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316286">(Sep 07 2020 at 17:32)</a>:</h4>
<p>is it? it more about the fact that you cant state facts about generator type in rust, is it not?</p>



<a name="209316361"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316361" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316361">(Sep 07 2020 at 17:34)</a>:</h4>
<p>Well, yes</p>



<a name="209316363"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316363" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316363">(Sep 07 2020 at 17:34)</a>:</h4>
<p>I guess I meant to say</p>



<a name="209316378"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316378" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316378">(Sep 07 2020 at 17:34)</a>:</h4>
<p>it's not obvious <em>why</em> we might need <code>Unpin</code> to be builtin right now</p>



<a name="209316382"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316382" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316382">(Sep 07 2020 at 17:34)</a>:</h4>
<p>until you think about generators</p>



<a name="209316402"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316402" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316402">(Sep 07 2020 at 17:35)</a>:</h4>
<p>specifically, we need to think about "movable" vs "static" generators</p>



<a name="209316484"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316484" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316484">(Sep 07 2020 at 17:36)</a>:</h4>
<p>im not familiar with the code backing generators, will it be a pain to represent the generator type in chalk?</p>



<a name="209316500"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316500" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316500">(Sep 07 2020 at 17:36)</a>:</h4>
<p>I don't think so. <span class="user-mention" data-user-id="125294">@Aaron Hill</span> has  a WIP PR up</p>



<a name="209316582"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316582" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316582">(Sep 07 2020 at 17:38)</a>:</h4>
<p>This makes me think: so, auto traits semantics and implementations for builtin types overlap a bit, in that both would cause a trait to be implemented for most builtin types. Don't know if this is meaningful, it's just something I haven't thought of before</p>



<a name="209316685"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316685" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316685">(Sep 07 2020 at 17:40)</a>:</h4>
<p>then it won't be too hard to support unpin anyway</p>



<a name="209316707"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209316707" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209316707">(Sep 07 2020 at 17:41)</a>:</h4>
<p>Nope. Just wasn't clear (without generators) why it needs to be Unpin</p>



<a name="209317007"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317007" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317007">(Sep 07 2020 at 17:46)</a>:</h4>
<p>so <span class="user-mention" data-user-id="335294">@memoryleak47</span>  you can either wait for generator pr to land and finish your pr after or rebase onto the wip pr if you are really eager to work on this</p>



<a name="209317302"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317302" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317302">(Sep 07 2020 at 17:53)</a>:</h4>
<p><span class="user-mention silent" data-user-id="232957">Jack Huey</span> <a href="#narrow/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22/near/209316582">said</a>:</p>
<blockquote>
<p>This makes me think: so, auto traits semantics and implementations for builtin types overlap a bit, in that both would cause a trait to be implemented for most builtin types. Don't know if this is meaningful, it's just something I haven't thought of before</p>
</blockquote>
<p>To elaborate on this a bit. Isn't a bit weird that scalars get auto traits auto-impled for them? Or maybe that's the only thing that separates it from <code>coinductive</code> (in Chalk terms). In fact, the docs <a href="https://doc.rust-lang.org/reference/special-types-and-traits.html">here</a> don't even mention that scalars get an impl automatically.</p>



<a name="209317376"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317376" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317376">(Sep 07 2020 at 17:55)</a>:</h4>
<p>depends on how you define auto traits</p>



<a name="209317401"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317401" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317401">(Sep 07 2020 at 17:55)</a>:</h4>
<p><span class="user-mention silent" data-user-id="251766">Areredify</span> <a href="#narrow/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22/near/209317007">said</a>:</p>
<blockquote>
<p>so <span class="user-mention silent" data-user-id="335294">memoryleak47</span>  you can either wait for generator pr to land and finish your pr after or rebase onto the wip pr if you are really eager to work on this</p>
</blockquote>
<p>I mean, I would recommend we just merge the PR once it looks good then we can update for generators when those are merged. But additionally, we do need the auto traits for builtin types done, but that's separate.</p>



<a name="209317453"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317453" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317453">(Sep 07 2020 at 17:56)</a>:</h4>
<p>if you define them as "implemented for types all members of which implement the trait"</p>



<a name="209317459"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317459" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317459">(Sep 07 2020 at 17:56)</a>:</h4>
<p><span class="user-mention silent" data-user-id="251766">Areredify</span> <a href="#narrow/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22/near/209317376">said</a>:</p>
<blockquote>
<p>depends on how you define auto traits</p>
</blockquote>
<p>Right, this is somewhat of a subtle point that I think is sort of "implied" but not well defined right now</p>



<a name="209317465"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317465" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317465">(Sep 07 2020 at 17:56)</a>:</h4>
<p>then its not that weird, because scalars have no members</p>



<a name="209317494"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317494" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317494">(Sep 07 2020 at 17:57)</a>:</h4>
<p>Well, of course they have no members, they're <em>scalars</em></p>



<a name="209317515"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317515" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317515">(Sep 07 2020 at 17:57)</a>:</h4>
<p>thats why they get a freebie :)</p>



<a name="209317521"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317521" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317521">(Sep 07 2020 at 17:57)</a>:</h4>
<p>Arguably, we <em>shouldn't</em> auto impl auto traits for scalars for the same reason we don't auto impl auto traits for foreign types</p>



<a name="209317734"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317734" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317734">(Sep 07 2020 at 18:00)</a>:</h4>
<p>I don't think this is semantics that can be changed. But it seems a little illogical</p>



<a name="209317881"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317881" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317881">(Sep 07 2020 at 18:03)</a>:</h4>
<p>we dont know what data is inside a foreign type</p>



<a name="209317900"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317900" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317900">(Sep 07 2020 at 18:04)</a>:</h4>
<p>so we cant say if it contains data of a type for which the auto trait is not implemented</p>



<a name="209317991"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209317991" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209317991">(Sep 07 2020 at 18:05)</a>:</h4>
<p><code>bool</code> gets an auto impl for the same reason <code>struct S {}</code> gets an auto impl - because nobody wrote a negative impl for them</p>



<a name="209318170"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209318170" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209318170">(Sep 07 2020 at 18:08)</a>:</h4>
<p>I 100% understand this point. I'm mostly just playing devil's advocate here</p>



<a name="209318196"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209318196" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209318196">(Sep 07 2020 at 18:09)</a>:</h4>
<p>(the docs I linked <em>should</em> be updated to also mentions scalars auto impl them)</p>



<a name="209318365"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209318365" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209318365">(Sep 07 2020 at 18:13)</a>:</h4>
<p><span class="user-mention silent" data-user-id="232957">Jack Huey</span> <a href="#narrow/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22/near/209318170">said</a>:</p>
<blockquote>
<p>I 100% understand this point. I'm mostly just playing devil's advocate here</p>
</blockquote>
<p>yeah I understand, scalars dont really fit in the "implemented for types all members of which implement the trait" thing</p>



<a name="209318377"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209318377" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Areredify <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209318377">(Sep 07 2020 at 18:13)</a>:</h4>
<p>but I convinced myself with the "no negative impls" argument instead</p>



<a name="209332259"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209332259" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209332259">(Sep 07 2020 at 22:52)</a>:</h4>
<p>No, I don't think that's quite right. <code>bool</code> and <code>struct S {}</code> both have as a member _the empty set_.</p>



<a name="209333103"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209333103" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209333103">(Sep 07 2020 at 23:09)</a>:</h4>
<blockquote>
<p>For any property P:<br>
    For every element of ∅, the property P holds (vacuous truth).<br>
    There is no element of ∅ for which the property P holds.</p>
<p>Conversely, if for some property P and some set V, the following two statements hold:<br>
    For every element of V the property P holds<br>
    There is no element of V for which the property P holds</p>
<p>then V = ∅. </p>
</blockquote>
<p>That is the real upholding logic here, no? Either we are taking the empty set as a member and so there is nothing that doesn't hold so of course we can make vacuously true assertions about it, or we are describing a scalar value itself as its own set and any particular value is a member of that set and the implementation in the first place is an assertion over all members of that set. Please feel free to correct me if I am wrong here! But I am pretty sure that this is relatively consistent for auto trait implementations over scalars.</p>
<p>( I mean the real reason is that it is relatively simple to handle most scalar values BUT )</p>



<a name="209556993"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209556993" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryleak47 <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209556993">(Sep 09 2020 at 19:30)</a>:</h4>
<p><span class="user-mention silent" data-user-id="232957">Jack Huey</span> <a href="#narrow/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22/near/209317401">said</a>:</p>
<blockquote>
<p>I mean, I would recommend we just merge the PR once it looks good then we can update for generators when those are merged. But additionally, we do need the auto traits for builtin types done, but that's separate.</p>
</blockquote>
<p>I agree. Can you re-review the PR? I think the book is actually correct already.</p>



<a name="209557079"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209557079" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryleak47 <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209557079">(Sep 09 2020 at 19:31)</a>:</h4>
<p><span class="user-mention" data-user-id="232957">@Jack Huey</span></p>



<a name="209565543"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209565543" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209565543">(Sep 09 2020 at 20:35)</a>:</h4>
<p><span class="user-mention" data-user-id="335294">@memoryleak47</span> seems like there was a problem with the rebase?</p>



<a name="209565657"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209565657" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209565657">(Sep 09 2020 at 20:36)</a>:</h4>
<p>But yeah, didn't realize, but book <em>is</em> correct</p>



<a name="209565668"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209565668" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryleak47 <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209565668">(Sep 09 2020 at 20:36)</a>:</h4>
<p>Irgh.. you're right.</p>



<a name="209567977"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209567977" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryleak47 <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209567977">(Sep 09 2020 at 20:59)</a>:</h4>
<p><span class="user-mention" data-user-id="232957">@Jack Huey</span>  ready now!</p>



<a name="209568426"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209568426" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209568426">(Sep 09 2020 at 21:03)</a>:</h4>
<p>r+ed</p>



<a name="209568447"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209568447" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209568447">(Sep 09 2020 at 21:03)</a>:</h4>
<p>Were you going to take a stab at the auto traits for builtin types?</p>



<a name="209568520"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209568520" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryleak47 <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209568520">(Sep 09 2020 at 21:04)</a>:</h4>
<p>Thats the next thing I'll be doing!</p>



<a name="209568535"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209568535" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> memoryleak47 <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209568535">(Sep 09 2020 at 21:04)</a>:</h4>
<p>Just wanted this PR to get through first</p>



<a name="209568727"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/144729-wg-traits/topic/Advice%20for%20%22Extend%20well-known%20traits%20by%20Unpin%22/near/209568727" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jack Huey <a href="https://rust-lang.github.io/zulip_archive/stream/144729-wg-traits/topic/Advice.20for.20.22Extend.20well-known.20traits.20by.20Unpin.22.html#209568727">(Sep 09 2020 at 21:06)</a>:</h4>
<p>Makes sense :)</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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